Test scheduling for modular SOCs in an abort-on-fail environment

Complex SOCs are increasingly tested in a modular fashion, which enables us to record the yield-per-module. In this paper, we consider the yield-per-module as the pass probability of the module´s manufacturing test. We use it to exploit the abort-on-fail feature of ATEs, in order to reduce the expected test application time. We present a model for expected test application time, which obtains increasing accuracy due to decreasing granularity of the abortable test unit. For a given SOC, with a modular test architecture consisting of wrappers and disjunct TAMs, and for given pass probabilities per module test, we schedule the tests on each TAM such that the expected test application time is minimized. We describe two heuristic scheduling approaches, one without and one with preemption. Experimental results for the ITC´02 SOC test benchmarks demonstrate the effectiveness of our approach, as we achieve up to 97% reduction of the expected test application time, without any modification of the SOC or ATE.